Lloyds Bank is the latest to take action over volatile crypto-currencies, banning its customers from buying bitcoin and its rivals on their credit cards.
The ban applies to Lloyds customers as well as those with cards issued by other parts of Lloyds Group, including Bank of Scotland, Halifax and MBNA.
It will only apply to credit cards, so customers who wish to buy crypto-currencies with a debit card can still do so.
The move follows volatility in the digital currency market, which sources close to Lloyds said the bank was keen to protect customers from.
On Friday (2 February) the price of a bitcoin dropped 15 per cent before rebounding, and other crypto-currencies followed suit.
Bitcoin ended last week down 30 per cent at $8,291 (£5,873) - its worst week since April 2013.
It had reached prices of $19,000 (£13,459) last November. However, the current price is still far higher than in January 2017, when it was worth just $600 (£425).
Prime minister Theresa May has also spoken out against Bitcoin, saying it can be used by criminals.
The Treasury is planning to bring virtual currency platforms under current money laundering and anti-terrorist financing regulations.
Facebook recently banned adverts for crypto-currencies from its site, citing large numbers of hoaxes and scams.
A spokesman for Lloyds said:“Across Lloyds Bank, Bank of Scotland, Halifax and MBNA, we do not accept credit card transactions involving the purchase of cryptocurrencies."